The United States and Japan will step up their defence cooperation to deal with the threat from nuclear-armed North Korea as tensions in East Asia remain high, officials from the two allies said on Thursday.

Tasmania ranked 'rotten apple' on health

Tasmania is more "rotten apple" than apple isle, according to new Heart Foundation health research.

The struggling state's population faces the highest risk of heart disease and stroke in Australia.

South Australians are the most likely to be overweight, but Tasmanians rank worst for high blood pressure, high cholesterol and low levels of exercise.

"(The study) has ranked Tasmania as the rotten apple in the basket when it comes to the number of people with key risk factors for heart disease and stroke including high cholesterol, high blood pressure, sedentary lifestyles and smoking," a Heart Foundation statement said.

Tasmania has the second-highest rate of smoking at 21.7 per cent, behind the Northern Territory (25.1).

Nearly a quarter of the state's population has cardiovascular disease, 30 per cent have high blood pressure and close to 70 per cent admit to a sedentary lifestyle.

"We can expect one in three Tasmanians will be affected by the disease by 2051 and we're very concerned that today's children are set to be the first generation in history to die at a younger age than their parents," Heart Foundation's Tasmanian CEO Graeme Lynch said.

The ACT is Australia's healthiest state or territory followed by the Northern Territory and - in equal third - NSW and Victoria.

West Australians and Queenslanders have the worst obesity rates after South Australians, while Victorians are the nation's slimmest.

"Heart disease is the single biggest killer of Australian men and women, claiming one life every 24 minutes and costing the health system $8 billion," Heart Foundation national CEO Dr Lyn Roberts said.